Hmmmm…
First, are your images still in your media library? Check the media library and make sure the images are there and displaying the thumbnails.
Second, what did you update? TagDiv? WordPress itself? Have you disabled all plugins and the theme and reverted to a core WordPress Theme like twenty-seventeen to check and see if the images show up?
Third, did you take a backup of your site before the upgrade? You should ALWAYS back up before the upgrade. You can use backup plugins like Backup Buddy or Updraft Plus, some hosts like WP Engine and FlyWheel have automated backups nightly, or you can VaultPress by Automnattic to backup.
Fourth, do you have any kind of CDN enabled? Are you using Photon in JetPack? Are you storing images somewhere else, like Amazon S3 and using Total Cache or SuperCache?
Lastly, it’s important to think about hosting with a company like WPEngine or FlyWheel that gives you LIVE, STAGING, and DEV environments, so that you can take your updates in a staging area, then push them live once you’ve tested them. You may want to think about adopting that process in the future, so that you can more easily troubleshoot your issues in staging then having a live site with no photos after an upgrade. Or, you should use a backup plugin solution to rollback to an earlier version if these things happen.
